I designed a symmetrical FET input folded cascode line stage preamp for Magnet Technology (Thailand) back in 1994-5, which was very successful in their home market and I believe it later won a TAS 'Golden Ear' award.

I have been out of the industry for a few years but am preparing a comeback with a 150W Nch monoblock on spec.

I don't have a copy on hand and would need a schematic drawing pkg to generate it but it was a symmetrical FET input (2SK170/J74 Vgs matched) with complementary TR folded cascode LED biased and EF output in a x10 feedback loop with servo. Simple, nice bits and remote with motorised alps vol. The market loved it.

The amp that won with it started life as a no global feedback company design with comp bip front end, cascode Vas and MJ15003/4 - sounded awful. I tricked it up with comp FET front end applied global feedback and finessed the compensation for much better 20K THD. Absolutely transformed. 2x200W from memory.

regarding your design - I have a great pref for sym FET input with the balance R no CCS. I don't see the need for the 2 stage output. The loadings light enough. My opinion.